— The study of terrigenous rocks of the Shatak Complex, which includes rocks of the Kuz”elga and Karan subformations (Mashak Formation, Upper Riphean) revealed numerous rare-earth minerals: allanite-(Ce), monazite-(Se), monazite-(Nd), xenotime-(Y), REE-bearing epidote, and unidentified compounds. It has been established that the detrital zircon plays the role of a selective concentrator of Y, HREE, and Th during the terrigenous rock metamorphism. The comparative analysis showed that rare-earth minerals, such as monazite-(Ce) and xenotime-(Y), in the Shatak Complex differ significantly (in terms of chemical composition) from counterparts in other complexes located on the western slope of the Southern Urals by the presence of Gd in monazite, and LREE (Ce, Nd, Sm) in xenotime. In the case of similar thermobaric parameters of rock metamorphism characterizing the alteration degree of lithostructural complexes in the Southern Urals, the chemistry of mineral formation environment is among the main factors governing the compositional features of rare-earth minerals.

This work presents new data on the Sm–Nd age of the Ishlya (1470 ± 62 Ma) and Misaelga (1481 ± 58 Ma) mafic/ultramafic complexes distributed along the western slope of the Southern Urals. The ages obtained are close to the Calymmian–Ectasian boundary ( 1400 Ma) of the International Chronostratigraphic Scale. Based on calculated data, it is shown that the area of magma generation for the melts that formed the named complexes has been located in the “head” of a plume, which is the primary cause of the Mashak “magmatic event” in the Southern Urals.

Research subject . Acid rock varieties of the Shatak complex were studied. Materials and methods . The reseach object included the previously unknown abundant mineralization represented by rare earth minerals. The concentration of petrogenic oxides was determined by the X-ray fluorescence method at the IG UFRC RAS (Ufa) using a VRA-30 spectrometer (Carl Zeiss, Germany) with an X-ray tube with a W-anode (30 kV, 40 mA). The amount of rare earth elements in the rocks of the studied area was determined by the ICP-MS method at the Central Research Institute of VSEGEI (St. Petersburg). The mineralogy was studied using a Tescan Vega Compact scanning electron microscope equipped with an Xplorer Oxford Instruments energy-dispersive analyzer (IG UFRC RAS, Ufa). Results . The studied rocks were diverse in chemical composition, varying from alkaline varieties (trachydacites) to low-alkaline rhyolites. These rocks belong to a highalumina type characterized by potassium specialization and a low agpaitic coefficient. It is assumed that the felsic varieties are subvolcanic formations, and the term “rhyolites” in this case characterizes the chemical composition of the rocks, but not their genesis. The amount of rare earth elements in the studied rocks is subject to significant fluctuations, varying from 60.81 g/t to 1625.39 g/t; moreover, their distribution is characterized by significant differentiation. In general, the rocks belong to a contrasting basalt-rhyolitic series, and their genesis is due to the differentiation of magma in the intermediate chamber. Numerous rare-earth minerals were found in the rocks, inlcuding allanite-(Ce), monazite-(Ce), monazite-(La), nioboeshinit-(Y), aeschinite-(Y), talena-(Dy), talena-(Nd), synchisite-(Ce) and Ce–La–Fe oxide. Conclusions . The presence of paragenetic associations of rare-earth minerals, such as allanite-(Ce) + aeschinite-(Y) + nioboaeschinite-(Y) and allanite-(Ce) + talena-(Dy) + talena-(Nd), indicate the formation of rare-earth mineralization in the course of a single process. The described type of mineralization has no analogues on the western slope of the Southern Urals, which substantiates the need for further research.

The Shatak Formation, comprising a part of the Mashak Suite (RF2), is located on the western slope of the Southern Urals. It consists of various rock types, including sedimentary rocks, such as conglomerates, polymictic sandstones, aleurolites, and carbonaceous clayey shales, as well as igneous rocks, including picrites, basalts, dacites, rhyodacites, and rhyolites, and volcanogenic–sedimentary rocks, such as tuffs and tuff breccias. In this article, oxyfluoride (La, Ce) (OnFm)3 mineralization, occurring in the contact zone between the metabasalts and quartz sandstones, is described for the first time in the literature. This is represented by compounds of variable compositions forming an isomorphic series: trifluoride, (La, Ce)F3–oxyfluoride, (La, Ce)OF–oxide, and (La, Ce)2O3. By analyzing several binary phase diagrams, significant coordination between oxygen, fluorine, and cerium in the chemical composition of oxyfluorides has been highlighted. However, the behavior of lanthanum has been shown to exhibit some irregularity. The genesis of oxyfluoride mineralization is attributed to the regional metamorphism of rocks within the Shatak Formation. During the hydrothermal process, the decomposition of fluorapatite, which is unstable during both hydrothermal metamorphism and supergene processes, resulted in the release of fluorine, as well as potentially lanthanum and cerium. Variations in the chemical composition of oxyfluorides, which are formed in the presence of an excess of oxygen resulting from water dissociation, are determined by local differences in the content of the main components within the forming microfractures.

The study of immune response and inflammation gene polymorphisms in a genogeographic context is relevant in the study of human populations. Here, in the indigenous populations of Siberia the frequencies of polymorphic variants -174G/C (rs1800795) and -572C/G (rs1800796) of the IL6 gene encoding the proinflammatory cytokine IL-6 were determined. For the first time, it was shown that the frequencies of the -174G and -572C alleles, which determine increased inflammatory response and are also associated with several diseases were statistically significantly higher in ethnic groups of Buryats, Teleuts, Yakuts, Dolgans and Tuvinians than in Russians living in Siberia. These values were in the intermediate position between those in the European and East-Asian groups. We hypothesize an adaptive role of these IL6 genetic variants in human settlement from Africa to the Eurasian continent. However, due to the departure from the traditional way of life and the increasing anthropogenic environmental pollution, the risk of diseases whose pathogenesis is based on inflammation in indigenous Siberian populations is likely increased.

The article presents the first data on rare earth mineralization in differentiated intrusions on the western slope of the Southern Urals. When studying the mineralogy of the rocks of the Shuida, Misaelga, Ishliy and Lysogorsk complexes, minerals of rare earth elements (monazite-(Ce) and allanite-(Ce), thorite (auerlite, cheralite)) and REE-bearing minerals (zirconolite-(Y) and epidote). A detailed analysis showed that igneous monazite-(Ce) and allanite-(Ce) are significantly different from the metamorphogenic analogues previously described in various structural-material complexes of the region. It is concluded that rare-earth mineral formation in rocks of basic/ultrabasic composition is due to differentiation of the melt in the magma chamber. Close temperatures of formation of minerals from different complexes (Ishliy complex – 958°C, Shuida complex – 950–954°C, Misaelga complex – 947–952°C) testify to the identity of the processes of formation of monazite-(Ce) and allanite-(Ce). opinion, the chemistry of the environment of mineral formation.

As a result of the studies carried out, it was found that the process of formation of sulfide and Fe-Ti-mineralization during the differentiation of the melt in the intermediate chamber consists in the crystallization of the sulfide and Fe-Ti melt, depending on its composition; crystallization of iss in the form of “intermediate” compounds, chromomagnetic and Cr-Mg-ilmenite, as well as the evolution of the composition of pentlandite towards Co-containing varieties. At the final stage, the process of decomposition of Fe-Ti solid solutions with a different number and composition of coexisting phases is realized.

The article presents materials on the P-T parameters of metamorphism of the rocks of the differentiated body of the Misaelga complex. Based on the study of metamorphogenic minerals and mineral associations: amphibole, amphibole-plagioclase, amphibole-garnet, epidote-garnet, muscovite, chlorite, ilmenite-titanomagnetite, a gradual decrease in temperature and pressure was established from the final stages of the magmatic stage of formation of rocks of the Misaelga complex to the beginning of the metamorphogenic stage. It is shown that the process of amphibolization begins immediately when the temperature of the residual melt drops by ~100°С (from 800°С to 700°С), which indicates the autometamorphic character of rock alteration. At the same time, the decomposition of the solid solution in titanomagnetite and ilmenite begins (766–588°С). Further changes include alteration (albitization) of plagioclase (550–>400°С), sericitization (~ 300°С) and chloritization (333–157°С). The association of minerals with garnet, distributed in a narrow interval of the section at a depth of 341.5 m with a horizon thickness of no more than 2–2.5 m, is a zone in which dynamothermal metamorphism manifested itself, due to fluid working out of the substrate of the Taratash complex in shear deformation zones, identified in the interval 1400–1200 Ma. The P-T parameters of dynamothermal metamorphism, determined by the garnet-epidote association, correspond to 550–580°С at a pressure of 2 kbar, and according to the garnet-amphibole geobarometer – 300–400°С. At the same time, it should be emphasized that these associations characterize the regressive stage of metamorphism.

Приводятся материалы по петрогеохимии и рудной Fe-Ti-Cr минерализации пород, слагающих дифференцированные (расслоенные) тела западного склона Южного Урала. Детальный анализ авторского материала показал сходство процессов перераспределения РЗЭ, благородных металлов и химического состава Fe-Ti-Cr минерализации практически по всем параметрам в породах мисаелгинского и кусинско-копанского комплексов. Установлено, что параметры метаморфизма, который повлиял на перераспределение компонентов в Fe-Ti-Cr минералах дифференцированных комплексов, соответствуют мисаелгинский – Т = <550-750 °С, P = 0,1-2,8 кбар, кусинско-копанский – Т = <550-630 °С, P = 0,3-0,7 кбар и шуйдинский комплексы – Т = <550-760 °С, P = 0,5-2,5 кбар. В результате моделирования процесса кристаллизации расплава показано, что кусинско-копанский комплекс представляет собой интрузивное тело, в идеализированном разрезе которого присутствует ультраосновной горизонт. Вследствие коллизионных процессов нижняя часть интрузива была оторвана от верхней. Предлагаемое строение кусинско-копанского комплекса резко увеличивает его перспективы на такие виды минерального сырья, как платиноиды + сульфидное медно-никелевое оруденение и/или хромиты.

Changes in (La/Yb) N , Eu/Eu*, t Nd (DM), and ε Nd (t) values in Upper Precambrian clay rocks on the western slope of the Southern Urals are considered. The (La/Yb) N , Eu/Eu*, and ε Nd (t) average values in Riphean and Vendian clay rocks are 5.7–15.1, 0.58–0.74, and –14.6 to –5.1, respectively. This reflects the change in the composition of the source areas and fits well into the general outline of subglobal events established by traditional geological methods in the conjunction area of the eastern regions of the East European Platform and the modern Southern Urals. The Early and Middle Riphean sedimentary sequences (1750–1250 Ma) were formed mainly owing to the erosion products of the mature continental crust of the East European Platform (t Nd (DM) = 2.8–2.4 Ga). However, the pre-Upper Riphean hiatus led, probably, to a significant change in the composition of source areas about 1 Ga. The increase in magnitude of ε Nd (t) to –5.9 and decrease in t Nd (DM) to 2.0 Ga in clay rocks of the Biryan Subformation of the Upper Riphean Zilmerdak Formation compared to underlying deposits suggest the appearance of the juvenile crust in the erosion area. This indicates the accumulation of fine-grained sediments at the beginning of the Late Riphean under the influence of active rifting processes, which is not recorded by traditional geological methods. The significant increase in (La/Yb) N (to 13.1 on average), decrease in ε Nd (t) to –14.6, and increase in t Nd (DM) up to 2.5 Ga in clay rocks of the Vendian Bakeevo Formation compared to the Riphean rocks are interpreted as the result of the accumulation of the Bakeevo deposits due to the supply of the products of glacial exaration of the basement mature rocks during the Marino glacial period. The significant increase in ε Nd (t) to –6.8 and rejuvenation of t Nd (DM) to 1.8 Ga in Vendian mudstones of the Basa and Zigan formations compared to the rocks of the lower part of the Asha Group reflect the appearance of a new mantle or volcanogenic material in the catchment areas during the Middle Vendian.

Materials on geochemistry and ore Fe-Ti-Cr mineralization of rocks composing layered (stratified) bodies of the western slope of the Southern Urals are presented. A detailed analysis showed similarity in the redistribution of REE, noble metals, and Fe-Ti-Cr mineralization of practically all parameters in rocks of the Misaelga and Kusin-Kopan complexes. It has been established that the parameters of metamorphism, which influenced components redistribution in Fe-Ti-Cr minerals of the layered complexes, correspond to Misaelga – T = <550-750 °С, P = 0.1-2.8 kbar, Kusin-Kopan – T = <550-630 °С, P = 0.3-0.7 kbar, and Shuidinsky complexes – T = <550-760 °С, P = 0.5-2.5 kbar. The result of modelling the melt crystallization process showed that the Kusin-Kopan complex is an intrusive body with an ultramafic horizon in the idealized cross-section. Due to collisional processes, the lower part of the intrusion has been detached from the upper part. The proposed structure of the Kusin-Kopan complex sharply increases its prospects for such types of minerals as platinum group minerals + sulphide copper-nickel mine-ralization and/or chromites.

The materials on the geology, geochemistry, and mineralogy of the differentiated body of the Misaelga Complex located in the Taratash metamorphic complex on the western slope of the Southern Urals are reported. The performed studies show that the distribution of PGEs and gold along the section of a differentiated body indicates its asymmetric structure. Comparative analysis of the normalized contents of noble metals in rocks of the complex and picrite of the western slope of the Southern Urals and the adjacent part of the East European Platform shows that the rocks are characterized by general tendencies, namely, the predominance of Pd over Pt and the “rhodium anomaly.” The REE distribution in rocks of the complex is characterized by their “inert” behavior upon intrachamber melt differentiation. The residual melt became sharply enriched in the entire group of REE only at the final stages. Detailed mineralogical analysis of silicates and aluminosilicates allowed us to calculate the P–T parameters of their crystallization: intratelluric olivine, 1472°C; olivine from the groundmass, 1050–1183°C; pyroxenes, 1071–1073°C; amphibole, T = 950–1045°C, P = 4.0–7.4 kbar. Variations in the chemical composition of the major rock-forming minerals and the internal structure of the differentiated body are satisfactorily described by the fractional crystallization model for the mechanism of directed crystallization with gravitational precipitation of olivine, olivine + clinopyroxene, and early-generation ore minerals at the initial stages of the massif’s formation. It is shown that the generalized process of the sulfide and Fe–Ti mineralization upon melt differentiation in the intermediate chamber includes crystallization of a sulfide and Fe–Ti melt depending on its composition; crystallization of iss in the form of intermediate compounds, chrome–magnetite, and Cr–Mg-ilmenite, as well as compositional evolution of pentlandite towards Co-bearing varieties. At the final stage, the decomposition of Fe–Ti-solid solutions with different numbers and compositions of coexisting phases occurs.

At present, great importance is attached to the problem of maintaining the professional health of the working-age population and prolonging professional longevity in the world and in the Russian Federation. This problem has become especially urgent in recent years, in connection with the change in the country's retirement age.

Russian Abstract: В настоящее время проблеме сохранения профессионального здоровья трудоспособного населения и продления профессионального долголетия в мире и в Российской Федерации придается большое значение. Особо актуальной эта проблема стала в последние годы, в связи с изменением в стране возраста выхода трудящихся на пенсию. English Abstract: At present, great importance is attached to the problem of maintaining the professional health of the working-age population and prolonging professional longevity in the world and in the Russian Federation. This problem has become especially urgent in recent years, in connection with the change in the country's retirement age.

The article provides materials on the analysis of the chemical composition of silicates and aluminosilicates that make up the differentiated body of the Misaelga complex, which made it possible by calculation methods to restore the thermobaric parameters of crystallization of the melt in the intermediate chamber. The presence of high-temperature (1472 ºC) intratelluric olivine crystals characterizing the process of magma generation in the mantle and olivine crystallizing under the conditions of the intermediate chamber (1050–1183 ºC) has been established. The calculated crystallization temperature of pyroxenes indicates that they crystallized together with olivine from the bulk of the rocks, and the established variations in the P–T parameters (T = 950–1045 ºC, P = 4.0–7.4 kbar) for plagioclase and amphibole complete the quantitative characteristics of high-temperature melt crystallization processes. It is shown that the calculated Р–Т parameters of the crystallization of the melt that formed the intrusive massif make it possible to classify its ultrabasic horizon as picrite complexes of the second type that we identified earlier. Modeling of the crystallization process carried out using two models – according to the algorithm of H.D. Nathan and K.K. Van Kirk and the software product KOMAGMAT – made it possible to establish that the most probable mechanism for the formation of a differentiated body of the Misaelga complex was directional crystallization with gravitational deposition of olivine at the initial stages of the formation of the massif.

The article provides a detailed description of Fe-Ti mineralization in the layered (differentiated) bodies of the Misaelga complex (Southern Ural). Various morphogenetic types of iron and titanium oxides are described: segregation ‘drop’, monomineral precipitates of ilmenite, magnetite, and various ilmenitemagnetite intergrowths and decay structures. The chemical composition of magnetite (in wt.%): TiO2 (from 0.13 to 14.27), Al2O3 (from 0.51 to 21.36), Cr2O3 (from 0.48 to 24.07), MgO (from 0.11 to 6.41), MnO (from 0.05 to 1.0), V2O5 (from 0.23 to 1.16), ZnO (from 0.8 to 5.78), NiO (from 0.13 to 0.73), SiO2 (from 0.52 to 2.75), CaO (0.51) and ilmenite: Cr2O3 (from 0.13 to 1.27), MgO (from 0.27 to 5.5), MnO (from 0.14 to 3.51), V2O5 (from 0.14 to 0.37), Al2O3 (3.0) and NiO (1.4). It is shown that chromium and magnesium in magnetite and ilmenite are present only in the minerals of the picrite horizon, where transitional magnetite → chrommagnetite and ilmenite → picroilmenite varieties are formed as a result of heterovalent isomorphism. Based on the calculation of crystallization temperatures, it was found that segregation of the ore melt occurred at T above ~ 1200 °C; the crystallization temperature of ilmenite–magnetite intergrowths was 712–745 °С, and the decay temperature of the solid solution varied within 588–766 °С. It is concluded that the segregation and gravitational deposition of ore minerals are not antagonistic but are realized at certain stages of the evolution of the melt. Moreover, the mechanisms of localization of the ore substance in a limited volume are governed by the physicochemical parameters and thermobaric conditions of the environment of mineral formation during ore genesis existing in a particular volume of the melt during its crystallization.